Disk drive and control method therefor

Abstract

Embodiments in accordance with the present invention provide a disk drive capable of verifying whether the speed of an actuator is true or not, the speed being detected while the actuator is being moved between a retracted position and a recording surface of a magnetic disk, and to provide a control method for controlling the disk drive. In a particular embodiment, a hard disk drive (HDD) comprises: a head for accessing a disk; an actuator for supporting the head, the actuator being driven by a voice coil motor (VCM); a speed monitor for, on the basis of a cylinder ID written to the disk, monitoring the speed of the actuator while the actuator is being moved between a ramp which is provided outside a data area of the disk and the data area; and a speed verifier for, if an abnormal speed condition of the actuator is detected by the speed monitor, verifying the abnormal speed condition on the basis of the counter electromotive voltage of the VCM. If the speed based on the counter electromotive voltage is also abnormal, the speed verifier records the speed as the overspeed.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The instant nonprovisional patent application claims priority to Japanese Patent Application No. 2006-117348 filed Apr. 21, 2006 and incorporated by reference in its entirety herein for all purposes.BACKGROUND OF THE INVENTION[0002]Devices using various types of media such as optical discs, magnetic optical discs, and flexible magnetic disk are known in the art as data storage devices. Among them, hard disk drives (hereinafter referred to as HDDs) have become popular as storage devices for computers, to such an extent that they are one of the storage devices indispensable for modern computer systems. Further, not limited to the computers as described above, HDDs are becoming more and more widely used in various applications. For example, HDDs are used for video recording / reproducing devices, car navigation systems, cellular phones, and removable memories for use in digital cameras.[0003]A magnetic disk used in the HDD has a plurality of da...

AI Technical Summary

Benefits of technology

The present invention provides a disk drive that can verify the speed of its actuator while it is moving between a retracted position and a recording surface of a magnetic disk. This is done by a speed monitor that detects the speed of the actuator based on a cylinder ID written to the disk. If an abnormal speed condition is detected, a speed verifier verifies it by analyzing the counter electromotive voltage of the VCM. This ensures accurate speed control and prevents damage to the disk surface.

Problems solved by technology

Until the head is loaded on the recording surface of the disk from the retraction area, it is not possible to read out position information written to the disk.

In addition, unless it becomes possible to stably read out the position information, it is not possible to switch to the positioning control of the head based on the position information (servo information).

However, even if an abnormal speed condition is detected on the basis of the result of reading out servo data at the time of loading, it is not possible to distinguish an abnormal speed condition caused by the damage to the disk or the head from an abnormal speed condition that is detected as a result of a failure to correctly read out servo data.

Therefore, it is not possible to know whether information written as the abnormal speed condition is true or not.

Images